SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92272cca303d95b7c3bde1252dc591df693d808753213dc43029b1f4d49e8e87' 
  AND token = 'peFRCMD+4vRy+9lS9qIan55YNRpiRj2TZGVd472GCIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00078

JSON explain

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