SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7301f382a7622d41f2f5897508391bda2f2e1addb22788c0f55e568da59368dd' 
  AND token = 'tO4sxUKgALKwozPoQNQvAXBQOTN+CWtOsWILMSCMDnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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