SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ad946a91d4527f58d7ba239f0db3eaac367ce62dce243f45ccaabab43a15d66' 
  AND token = '3i28IhbYWMck8/S4uHGZ1ytjYhF5dpV7SDEp7zbzYSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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