SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cb54ee94e139d4261758891084d1fa2c304228929c09297f4f19f142a08fdf01' 
  AND token = 'x21MNEZqC6GnCBjymFhNEUWnO4lPBenoqT02RHK4DUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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