SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0eebfca97d7a846fff84afbc6d153dfd8b0cd626644328e74f4c51f2f15878cc' 
  AND token = 'CQpyJSa2GEM6nCjINL1pYpM/NQ2IZ8MS5jFQbFNWy/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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