SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '086d2dca76edcec98a83e916da304324a390bd4a29223367989ae0b6434192cd' 
  AND token = 'GFLqm3Eto2nRCMudgFN6Oip+dKhIQ7PUAaYeRtkoEt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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