SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4c52692103bb361eb37f33a9b92df99881cfec220df0a31c7d6298da10a6ddf' 
  AND token = '1RtdDh1EpOHrirfVy3iBIh8jxjRn6nv9z+v/viKOtQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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