SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca2f8f511d6902b5a2994e9e4ebf1a21d84868c24b09a5f9a062fc746a132f1b' 
  AND token = 'E8uhWqMOW1VqPpRrpCiCteKcfVhizCy0hRDTDV1OxAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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