SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d300569684375c28425bc72b8a7b36041bf39edf537e4c9189382f0ef420134' 
  AND token = 'CZJHA7iWYdwfV3i7c3vZIzan5+vfELAMesJ/rMN9gkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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