SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '618a37554a021efcf7bb42fec12890f8713cf33852db8b2080364b8d0a01c3ad' 
  AND token = 'aN/zRhGVXkYWY2TvtPQQVhFEEkg1oD46gq8MnUhbQ3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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