SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97c714399574a558769a971031eff7ef0c3313e6e061e793137836b565bf4b16' 
  AND token = '2FTj15Ty6xAr6Jek5pJKzI+ChhroKkLkKbYAV4r8N8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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