SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b2a93861f74c046d986b35a03b8d152cca06ff00b8a91889bde35876803c4e' 
  AND token = 'hAuW4jOBYUlXcZTrefrLc+AFGOB+S/QHEhZqdNS74h4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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