SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '54339c6d14107859f25b6ab9a96f182deb6fcbc0a0a727441de0b624d2188e29' 
  AND token = 'mbDI5Naox+s3mbq61iUCjAYg502HzzV40cPNkXRXuEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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