SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e91b52b82a12f0a55176952a257144bf211479afbd0d1f620c9fc1985560c89d' 
  AND token = 'Apt9YkugSjnl8ZRo19LpjX8ZDKgshVuYfFo6lsvUBmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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