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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6e8ed7e5ef95d76984e3ea988f7619c444621ba4b68fbf4e654efd0b1968481' 
  AND token = 'EU8fy/yX7NNRJJzrIXy3hfifpBHuJ8O87ymGQD8OsAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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