SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3076b90abeaee85c631f7e142805e248c8cadcd59992c54190384bde2c9ce088' 
  AND token = 'Y96XIG7x3v+fwrPyZORMduWPxJ6PAMspQebJAg+pFe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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