SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870d9766e5528ba28cacd29229b0bf026cd3ecde6dea1dbe206c68d423343aa5' 
  AND token = '4eg1wy7KIKcZtVGbVtnn26YsQEeVykz9lYKaCV3skWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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