SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '556d188e42317979b78e2b466bd1d7ad0969381523f85db05b2cdcc616c19fb1' 
  AND token = 'zbcw3VtcFP7u0EdUJsuAXUfdQwmqBwVQmqYrGrdRbdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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