SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd7659afab67d18bea92f921ade8a1caf6319ceaa9297fe5aa528236d66a41b6' 
  AND token = 'DAfTJIGHuz8gilQo2BIt5KkwjxHhYq4ADAuvyF+AcWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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