SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '740c4bd30ce62be9a46f86582aaa098fbc40305511dd8902d6670c08f6141adf' 
  AND token = 'zQlLuuWCPtr+XTWKHsJ7/C0/qYg11SY2XsQJ7XXoKMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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