SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6162662f5ae2d4f59980a42d8eb83fd8fceae1fe636f414d60e4bb5f36ff4599' 
  AND token = 'PgTTcQDGKqwQbd0/bIZYZt03NP8UJKjsapCthH+ZyoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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