SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f70438e0beb888d74877df66e68e409219f8e1e282b1e5fa806eab4445bf757' 
  AND token = 'lXZJJKEIaBnrdumf1Ts4CqSetZF6uvjWHPwsJ8IoNCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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