SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4bf1082db29f063be09b5346ba050d6232c0a95b145934386c318ad8499d234' 
  AND token = 'zPCWDqe+XagSBNDFqf9JYLjR+xDQjOcT6LTxLaeT7qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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