SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2528dee09e085e94a6dc8a1b7a13debeddefc295f30f77952d25ce52ffdd017a' 
  AND token = 'Ixs4BVJ1ecc+5aFOPKBnyuwayiezd+VKPdjeUOezpM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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