SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '623cfe34903600d757abd106451869801c679995a1128f2e73115d1e3a17e5a3' 
  AND token = 'Z6sunUVKkwttaXyRpA8C1NklY2JykgqkRk0bWqMNb+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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