SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0b4c491d805045d31d79c632ae7bfef5989fa17d7fb44c59fd9ba41bcebc0b6' 
  AND token = 'OiPk60DUIzN0FC8miicFxrDDkf3f15YN2AvZToys+vY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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