SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62a84c02f2ed798493f88e3ebdda3c7bd9466dea5a6cf0e95133be20d2ef6fc7' 
  AND token = 'oxwet+Fw984vWiZqnyo8c0bDm5TtoXFH0kj1yPIgyjo=' 
  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"
    }
  }
}