SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '713a782ca306d9b0462db835f5fecaf003296c5e1f67b42d35e5c05a15d03143' 
  AND token = 'kWhsZIEcC2wQz0ZPjCzsfRnPRRVVN/Hc8XFp4wlpAzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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