SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb46234bea2fcdd2973aca6e16533085cce7e3fc88da26801b710b7672b2367f' 
  AND token = 'HeeS5QHTztKYyHrWtNN1KiLzqJC96gL3xyEz/ukpmfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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