SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a2650da17c83f48c6899a719b883d003fafd7811a62612edca9a5638744f744' 
  AND token = '5uhUG9+kf5FnXSyfOaIVi+eOL8jkbGexinEVnazLPA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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