SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e63e3219031009822bead25ae92e60dcc92100db1246d54dbea12ebf471dcfff' 
  AND token = 'dz4bIjFDTbPqs1kqYHAO2dRAmiT8xZSFvGVtBj2LpEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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