SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc76d0d23d25adc7a03190cfa872c8edd52bf08ad9519aa192c7475df7c05b83' 
  AND token = 'RzxsWR2psytq3QYApqdqAuin7ttP5iSI5D1xZ2znZ7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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