SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e77212c0083adda5bb3b0ca0e199def9ec6c68262f54b037d500f8a031a0ed9c' 
  AND token = 'lrwdWaltcFeNjTqfQTTJOLUxxsRem/MWIHqFmEwKyu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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