SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d6700fb86f26188dffd5f5880c711426bf8aba8f82fcd5136cade917da75e62' 
  AND token = 'YZ9pT/IKEnG3c+F9luS+lwq1pX/Hl14zuZrYbtsC1io=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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