SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a35352b56ec95d4460c7252ca293798e49adcda8f16ff7009aff0688aaff7cc4' 
  AND token = 'K+eCUripHr0F0s9gLmMyuoEcRzkW5QuD1pCbZO9fUM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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