SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ad7d6641732dd5792e72aea4ee4b2bf15773984d155ea8f9e4236f537a31c9' 
  AND token = 'wzz+CrdZcBjKZoqvPA/sPoGiF1f/B5TTqCeACkoqJD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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