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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a06d6c8b4ef2c54c92bf3a0959c5d51bd5a93d3a13ddcc3abc10683d27c462d' 
  AND token = 'KxOdh0QM63SmlMlQvVrv/YOiWQewUJ91BzHzNs4EDks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}