SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf8eebfa375b0393128027547278e484f9f88dd41e336f281ca39c11954bf5b0' 
  AND token = 'L2NfBTWwKRkqAWhHqVDu7ey8BFErYsKfrhzP6brTFXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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