SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b77834a4a8e93f05f0644d4f361d8d2b8e450ac9bc5261f7994a7c170199f43' 
  AND token = 'RgT2bjVrX2s0PPexZu1WFgW1dvX3tYJ48S+TKheBhok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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