SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2cdcd8d84ac599fde517d92567ab6785494f6261c6d447e503fc700f2d0887b' 
  AND token = 'q5NFMz/uXry2gYGWZVz3AAx9d15IX/bPHBmEchuKY88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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