SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9965470d7299536a1e65856fb9ed0ec4dad835da87e8c09291264b78ba5ed9ab' 
  AND token = 'gRDzqgh7YymBpEahMenVUpDmkrP6x5wHBJDpYcVs/bQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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