SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eda35a7142aa3f815534f23793b8c258c7f7f1532e750899d3660266f815acd' 
  AND token = 'Ek2EBJFU0p2BHXb4KRxHYBOUhF0ovJ1E2sZkKlyI91U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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