SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542451faa539ec322fed5dcfdf7873b16647d04b9f276049d42b89e7b7692fd7' 
  AND token = 'aTrGK+RimVJROT8WtD4dGszBhUJhqNCzjzGBH3L9Ccw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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