SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'da090aa783cbe09001b43e3e9b0d8d78f352c676fb5b893b92acee96517049e3' 
  AND token = '+7ABwUN889sqCvur4Nnqh11AVwuQHV7Tc6KoLJnTOMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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