SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '33cb24bed629e2343e28635ed052510b738d758f5708649e86288a993decb2a9' 
  AND token = 'zwvuZjzOsjBEb1HFzRycYuEaFc81Y+kz9PN1rMmCNxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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