SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7caac2612f64db439f0b801e8ca7734a006a273ff4aec655ed370e1fc931d2f' 
  AND token = 'XvwjW01Hck5zDQX1+ap+Bm/Yz2GgBqZO14SO/IeU1LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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