SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fe2f57564ef102bee3f688eca477ca0a13a50a7d4184c6f0d70e69e88219b85' 
  AND token = 'B6Q603jaGMDu+F5nc57fl2wtp9WU0VVCw8th8NhpZ+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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