SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6caff717b3c9646a98782997049e42eb92677e4e02089cf1a76fcf66de106236' 
  AND token = 'biGUiUUX8Zd+4CNQ8xPM7YjyUotPoNWsS7H2eRXH/u8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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