SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d64283f85ed07e8dbff72a1555a9b9276fa47743d389fa236015fb4476a197a' 
  AND token = 'Uj95YlTt3WS/unXuEkaBC+oFtJnbXmwFqO1f0QJZfY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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