SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d5d98231895183009abe1e8f909388c62e603479506ed0119d239080ffd1e48' 
  AND token = 'X5a5gpjHJ8rkfJMbM+kITopGLuy2ehRbEOL9zMsspzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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