SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5fdf5bebed69b0aed97124d8179589f6746a7a0a47f5cd5e360252e492cecb3a' 
  AND token = '5Bg4iZGa+id83kSwovm/waKoYa5e/881z0jQCGVW9yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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