SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b248a6bbb2b3166552fd721b3c59704d88ef7c5cb70f62d4d61a79ac5b92b439' 
  AND token = 'EdtQiuEgc+gexJ56OcELJ/t2HFyyogFjgVIsIBfquWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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