SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d53366805533228641456ddd4b296f9b8dcd57adea3c0bb29e26a738d2c9e85' 
  AND token = 'xB7s/G/qvaoBODmFRnHrqJKnfYGFda1n91MHkJWNKME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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