SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a68c1ad7d1c3fc05b44f6754ae55b7578846a54c59275f9723dd9dd6a98b624d' 
  AND token = 'yHjCVqS3TQNG0rGbE/Tlc4YPgwQeWyrFpzuM1gNPkh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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