SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c60d9fdcaba61b474f094218bf709a2af5ad3db4f096cb819aca1ab35e44081' 
  AND token = 'Kn4ERl52h1JhIIJA4ezvduLf2nunDLGQPQNzBIMI7mE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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