SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92ca122dfe5d3afdd0081d2c51b91521a7d1f2fd6e56ddc439f89336bf3eba71' 
  AND token = 'UWDPhZjXYYljEXvUbH2i7Twcs+W2CsYUHFlVqKUvp9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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