SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e915d235445e422816e8dd6baca996a84e1d821d64bca4dfcc1608941327d7c6' 
  AND token = 'ra0k5vXkoiPXOlpTp6Tm07KYSL7YPpTEgZdtF6St8w0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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