SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2adc83bc14f8020ba09ab12bf44f816b1841e0db9aa72e322efa9d0655657302' 
  AND token = 'As144rPADMKQKbK51xx088+VKbqPfOWzZHT1sP3Mgro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}