SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e7159707cf9da1a9592911805eebf1a2202aec2e1852d1bfa8e21d7f9fa7d80' 
  AND token = 'VfGLZUj0x02OmlChFfbor+7EmVcvRxNmi9pWUfrKgcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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