SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '668201f241b218dd40c017692410cb6afd59bf5009612dc1ce2a986d39ff983f' 
  AND token = 'Gxz3ETC2HuzuOpjV+Z7GxxAqm5IGCGZe+h40qC0AT9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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